Researchers from the Higher Technical School of Agricultural Engineering of the University of Seville have proved it would be necessary to have 207 and 740 hectares of green roofs, depending on the scenario. The researchers believe that this would reduce the effects of climate change in relation to the maximum temperature rises that are estimated to happen by the end of this century. This would require between 11 and 40 percent of the buildings in the city to have this technology.
The researchers used Landsat 7 ETM+ and Sentinel-2 satellite images to obtain the normalized different vegetation index (NVDI) and ground temperature. Given the inverse relationship observed between their values it has been possible to determine the additional area of vegetation needed to reduce the temperature by the same amount that it is predicted to rise in different change models.
"To mitigate the effects of climate change, we can talk about two types of options: to attack it at its origin, by eliminating or reducing the human factors that contribute to it (such as, reducing emissions, controlling pollution, etc.) or developing strategies that allow for its effects to be reduced, such as, in the case that concerns us, increasing green areas in cities, using, for example, the tops of buildings as green roofs," said Luis Pérez Urrestarazu, University of Seville researcher.
The installation of these gardens would provide better insulation for the buildings, energy savings for their owners -- and if there were sufficient green roofs -- an improvement in environmental conditions contributing to reducing pollution and cushioning the higher temperatures.
"To fight against climate change, this is a necessary strategy at a global level," said Pérez. "However, local measures can be established that contribute to this global strategy and which can help to reduce the local effects that might be produced in one's own city."
The University of Seville research group ‘Naturación Urbana e Ingeniería de Biosistemas’ works on different projects connected to non-conventional urban naturalization, specializing in vertical gardens, and aquaponics, join the production of plants and fish.